title: Quantification of cell specific uptake activity of microbial products by uncultured Chloroflexi by microautoradiography combined with fluorescence in situ hybridization.
abstract: We, for the first time, quantitatively determined cell specific uptake activities of microbial products (bacterial cell detritus and extracellular polymeric substances, EPS) by the member of uncultured Chloroflexiby using a microautoradiography combined with fluorescence in situ hybridization (MAR-FISH) technique. For this MAR-FISH analysis, we prepared [14C]-labeled microbial products from biomass sludge obtained and bacterial strains (Pseudomonas sp. and Acinetobacter sp.) isolated from our pilot-scale membrane bioreactor (MBR) as tracer substrates, which probably represent the more realistic food source in the MBR. The quantitative MAR-FISH analyses clearly showed that most of the uncultured Chloroflexi could indeed uptake the bacterial detritus of the two isolated strains with rates of 1.7-3.5 x 10(-7) g-C microm-2-surface area h(-1) (corresponding to 1.2-1.7 mg-C-bacterial detritus L(-1) h(-1)) in the cultures, which were, however, about 2 orders of magnitude lower than the uptake rates of simple monosaccharides (mannose, arabinose, fucose, and galactose). Based on these results and their high abundance (more than 20% of total bacteria detected with EUB338-mixed probes), it could be estimated that the uncultured Chloroflexi contributes 38-51% of the total degradation of microbial products occurred in the MAR-FISH cultures.
authors.affiliation: Department of Urban and Environmental Engineering, Graduate School of Engineering, Hokkaido University, North-13, West-8, Kita-ku, 060-8628 Sapporo, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okabe
mesh_terms: D000150:Acinetobacter / Q000378:metabolism; D001345:Autoradiography; D001704:Biopolymers / Q000378:metabolism*; D019149:Bioreactors; D002138:Calibration; D002250:Carbon Radioisotopes; D041862:Chloroflexi / Q000166:cytology* / Q000378:metabolism*; D003470:Culture Media; D017404:In Situ Hybridization, Fluorescence; D007211:Indoles / Q000378:metabolism; D009005:Monosaccharides / Q000378:metabolism; D011549:Pseudomonas / Q000378:metabolism; D012722:Sewage
chemical_list: D001704:Biopolymers; D002250:Carbon Radioisotopes; D003470:Culture Media; D007211:Indoles; D009005:Monosaccharides; D012722:Sewage; C007293:DAPI